1
Q
What are the QCs for sample container supply and receipt (bacti bottles)? Where is this check recorded?
A
- Checked for sterility, chlorine quenching, fluorescence, and volume by lot # (pass/fail basis)
- Recorded in the Bacti Bottle QC Check Logbook
2
Q
Lab environment: what must you do before and after working with samples?
A
Spray surfaces with 70-91% IPA or 10% bleach and wipe dry
3
Q
How long/what temp do you autoclave media?
A
15 min @ 121°C
4
Q
Thermometers are calibrated _____ against a NIST traceable reference.
A
annually
5
Q
Temps are recorded _____ times a day, at least _____ hours apart.
A
2x a day, 4 hours apart
6
Q
What temp must the autoclave be able to reach?
A
121°C
7
Q
BI capsule:
1. How often?
2. How do you do it?
3. Why?
A
- Monthly
- Autoclave BI capsule with biohazard (cycle 3)
- Incubate in hot block (55-56°C) for 48 +/- 3 hrs
- Pass = purple/gray
- Fail = yellow - To make sure the autoclaves is effectively killing the bacteria
8
Q
How do you do the quarterly autoclave timing check? Why do we do this?
A
- Record autoclave timer read out and stopwatch time to the second for each minute of the cycle
- Must be +/- 2 seconds
- Calibrate the stopwatch annually
- Why: to make sure the autoclave cycle is going long enough/not too long
9
Q
Balances are verified _____ by the lab with a NIST certified weight set.
A
monthly
10
Q
Test the UV lamp _____ with a UV light meter. When should you replace the bulb?
A
- quarterly
- Replace bulb is <70% original intensity or annually
11
Q
Pipettes and dispensers are verified _____.
A
quarterly
12
Q
Disposable pipettes are volume verified _____.
A
with each new lot
13
Q
How do you do the volume check for pipettes?
A
- Pipette volume at the top of the pipette range
- Pipette the RGW into a plastic cup that is tare on the balance
- Record the volume pipetted and the weight of the water
- % recovery: +/- 2.5 %
14
Q
How do you wash glassware?
A
Washed with Alconox, rinse 3x with warm water, rinse with DI water
15
Q
How do you do the annual inhibitory residue test?
A
- 4 groups of 6 petri dishes
- Group A: routine-rinsed
- Group B: well-rinsed
- Group C: unrinsed
- Group D: pre sterilized plastic - Do HPC and count plates and calculate average for 3 plates
- Use formulas to compare each group of plates
16
Q
Why do we QC check the RGW?
A
To ensure it’s free of bacterial and inhibitory substances
17
Q
What are the monthly checks for RGW?
A
- Conductivity (<2 umhos/cm at 25°C)
- Total organic carbon (<1 mg/L)
- Total residual chlorine (<0.1 mg/L)
- HPC (<500 CFU/mL)
18
Q
Quarterly use test for RGW:
1. Why?
2. How?
A
- Compare old lot vs new lot
- Replicate of 5 HPC plates using culture dilution of known concentration
- Use KA 30-300 CFU/mL
- Count plates and convert counts to log10 values
- Compute difference between pairs of plates (including + or -), average, and standard deviation of the 5 differences
- Calculate student t value: </= 2.78
19
Q
What are the annual checks for RGW?
A
- Heavy metals
- Water suitability test
20
Q
How do you calibrate the pH meter?
A
- With pH buffers 4, 7, and 10
- Slope: 95-105%
- Verify calibration with a second source pH buffer
21
Q
The QT sealer is checked for leaks _____.
A
monthly
22
Q
How do you do the QT sealer check?
A
100 mL buffer water in a bacti bottle and add Bromocresol purple
23
Q
What are the bacti bottle QCs (every new lot)? How do you do each one?
A
- Sterility check: 100 mL 2x TSB, incubate at 35 +/- 0.5°C for 48 +/- 3 hours
- Volume: fill with RGW on tared balance, % recovery within 2.5%
- Residual chlorine quenching: get 100 mL of 15 mg/L residual chlorine from chem
- Add chlorine reagent into bottle and shake to mix the sodium thiosulfate
- Dip chlorine strip into bacti bottle: result must be <0.1 mg/L - Autofluorescence check
24
Q
What are the weekly QCs?
A
- Counter swab
- Autoclave max temp check
25
What are the monthly QCs?
- BI capsule
- UV bulb check
- DI water HPC
- QT sealer check
- Within and between analyst repeatability of counting
- Balance verified monthly with a NIST certified weight set
26
What are the quarterly QCs?
- Autoclave timing against a stopwatch
- UV lamp test with UV light meter
- Pipettes and dispensers (volume check)
- Use Test (comparing old water lot to new lot)
27
What are the annual QCs?
- Thermometer calibration against NIST traceable reference
- Annual autoclave maintenance
- Stopwatch for autoclave timing check
- Balance calibrated by ISO 17025 certified vendor
- Replace UV bulb annually or as needed
- Inhibitory residue test
- Check RGW for heavy metals and water suitability test
28
What are the applicable matrices for HPC?
- Source water
- Potable water
- Non-potable water
- Finished process water
29
What is the nominal detection limit for HPC?
1 CFU/mL
30
What are heterotrophic bacteria?
- Opportunistic pathogens
- Can cause problems for distribution systems
- No severe health risk but can cause unfavorable taste and smell
31
Why do you run a dup (HPC, MTF)?
A dup can indicate precision associated with lab procedures by removing variations contributed by sample collection, preservation, and storage prodecures
32
What are the HPC holding times for:
1. water
2. solids
3. swabs
1. 8 hours
2. ASAP
3. 24 hours
33
What is passing for the weekly counter swab?
<15 colonies
34
What do you do if a QC fails?
- Tell the PM
- They'll contact the client
- Client can decide if they want the results reported (if results are still reportable) or if they will resample
35
What is passing for moisture loss for HPC?
<15%
36
What are the applicable matrices for MTF?
- Drinking water
- Waste water
37
What are the nominal detection limits for DW and WW MTF?
- DW: 1.1 MPN/100mL
- WW: 1.8 MPN/100mL
38
What is a negative invalid? What do you do if you get a negative invalid result?
- DW MTF only
- When there is growth no gas in the presumptive phase --> transfer to ALL medias
- If confirmed and completed phase are negative --> report as negative invalid
- If positive --> report MPN
- if TC negative but FC and EC positive --> report MPN
39
What is the purpose or Bromothymol blue?
It is used to test for acid/base residue in washed glassware
40
What are the QCs for washed glassware?
- Bromothymol blue to check for acid/base residue (should stay green, if it turns blue there is residue and the glassware must be washed again)
- Fluorescence
41
What is the nominal detection limit for HPC?
1 CFU/mL
42
What is the nominal detection limit for SimPlate?
2 CFU/mL
43
What is the nominal detection limit for Enterolert and Quanti-tray?
1 MPN/mL
44
What methods test for E. coli?
- P/A
- MTF
- Quanti-tray
- SimPlate
45
What methods test for total coliforms?
- P/A
- MTF
- Quanti-tray
46
What methods test for enterococcus?
- Enterolert
- Strep/entero MTF
47
What methods test for streptococcus?
- Strep/entero MTF
48
What methods test for fecal coliforms?
- MTF
- Quanti-tray (but not approved for drinking water by EPA)
49
What are the applicable matrices for strep/entero MTF?
- Ambient water
- Groundwater
- Wastewater
50
What are the applicable matrices for SimPlate?
Potable water
51
What are the applicable matrices for Enterolert?
- Non-potable water
- Wastewater
52
What are the applicable matrices for Quanti-tray?
- Potable water
- Non-potable water
53
Why is fecal Quanti-tray only done with Colilert 18?
Because Colilert and Colisure are not approved by the EPA for testing for fecal coliforms
54
How do the medias work (colilert/enterolert)?
The media contains chemcials that react with enzymes the target bacteria produce that results in a color change and/or fluorescence
55
How do the MTF medias work?
Inhibit the growth of Gram-positive bacteria and provide nutrients that support the growth of the target bacteria
56
What are the pH ranges for the medias?
LTB: 6.6 - 7.0
EC and EC +MUG: 6.7 - 7.1
HPC agar: 6.8 - 7.2
BGBB, buffer water, and ADB: 7.0 - 7.4
BHIB (w/ and w/o NaCl): 7.2 - 7.6
BEA: 6.9 - 7.3
TSB and TSA: 7.1 - 7.5
57
What does it mean if a sample turns brown during incubation?
- Has high levels of metals
- Non-reportable
- Tell PM
58
What is the code for presence/absence?
SM 9223 B-c
59
What is the code for Quanti-tray?
SM 9223 B-b
60
What is the code for HPC?
SM 9215 B
61
What is the code for SimPlate?
SM 9215 E
62
What is the code for Enterolert?
SM 9230 D
63
What is the code for strep-entero MTF?
SM 9230 B
64
What is the code of MTF?
SM 9221 B (total), E (fecal), F (E. coli)
65
Walk through the steps of a SimPlate.
1. Make sure you have proper PPE on (lab coat, goggles, gloves)
2. Get samples
3. Prep the logbook
4. Turn off AC
5. Sterilize work area
6. Prepare the media by adding 100 mL of sterile water
7. Pipette samples onto plates (1.0 mL for 1x, 0.1 mL for 10x)
8. Pipette media (9 mL for 1x, 9.9 mL for 10x; total volume must be 10 +/- 0.2 mL)
9. Prep QCs
10. Incubate for 48 +/- 3 hours at 35 +/- 0.5°C
66
Walk through the steps of a strep/entero MTF.
1. Make sure you have proper PPE on (lab coat, goggles, gloves)
2. Get samples
3. Prep the logbook
4. Set up tubes (2x ADB, 1x ADB, and 1x ADB)
5. Pipette 10 mL, 1 mL, and 0.1 mL of sample into each row
6. Incubate for 24 +/- 2 hours at 35 +/- 0.5°C
7. Read tubes and transfer any tubes with both growth and gas to BEA
8. Reincubate the ADB tubes (48 +/- 3 hours based off original incuation time) and incubate the BEA plates for 24 +/- 2 hours at 35 +/- 0.5°C
9. Read the ADB tubes: transfer all +/+ tubes, no more reincubation
10. Read the BEA plates: transfer colonies to BHIB and BHIB w/ NaCl
11. Incubate the BHIB tubes in a water bath at 45 +/- 0.5°C for 40 +/- 3 hours and the BHIB w/ NaCl tubes in an incubator at 35 +/- 0.5°C for 48 +/- 3 hours
12. Read the BHIB and BHIB w/ NaCl tubes: growth and gas are positive
67
Also be able to walk through the steps of P/A, Quanti-tray, Enterolert, MTF (drinking water and wastewater), and HPC! Good luck, you got this!
68
List all the methods.
1. SM 9223 B-c: presence/absence
2. SM 9223 B-b: Quanti-tray
3. SM 9215 B: HPC
4. SM 9215 E: SimPlate
5. SM 9221 B, E, F: MTF
6. SM 9230 B: strep/entero MTF
7. SM 9230 D: Enterolert
